[PATCH] D45448: [CVP] simplify phi with constant incoming values that match common variable edge values

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

In https://reviews.llvm.org/D45448#1062055, @efriedma wrote:

> Any idea how often this triggers in practice?


I didn't, but I added a debug stat and built test-suite -O3. This fired 94 times across 48 files.

For some context, the existing CVP phi optimization counter shows that it fired 6758 times across 680 files. That one counts both the existing threading over select transform here in CVP and any folds done by instsimplify when called from here.

Not sure how to judge this data in the larger context...rare, but not impossible, so worth the effort of looking for the pattern?


https://reviews.llvm.org/D45448